The present invention relates generally to bearing wheels for use in conveyor systems and the like.
Bearing wheels in conveyor systems typically comprise an axle to which the inner race of a ball or sleeve bearing is fixedly attached. The outer race rotates to act as a wheel. The inner race has been conventionally riveted to the axle, which disadvantageously requires that the axle be destroyed to get the wheel off. Moreover, when the wheel begins to wear out, it becomes stiff and the outer race stops rotating. As a result, the inner race starts rotating on the axle and wearing the rivet away until the wheel falls off, requiring a shut-down of the conveyor system and associated equipment. It is important to the operator not to have to shut down the system since such down-time is very expensive. The operator would therefore prefer to have a warning of wheel failure so that repairs can be made at a convenient time to avoid such a costly shut-down.
U.S. Pat. No. 3,602,150 discloses a suspended trolley construction for a power-and-free conveyor system, wherein a central casting is supported by a shaft to which wheels are attached to the shaft ends, the wheels rotatable along rails. Each wheel has an inner race and an outer race separated by bearings. The inner race is removably fixed to the shaft by an end plug which threadedly engages the end of the shaft and which has an expanded head which bears against an annular bevel of the inner race. A slot is milled longitudinally along a side of the shaft and is engaged by a radially inwardly projecting lug of the inner race to key the inner race to the shaft and thus prevent relative rotation between the shaft and inner race.
Undesirably, the screws holding the inner races on the axle of this U.S. Pat. No. 3,602,150 may loosen to cause the wheels to come apart. In addition, the radially extending lug, with its small cross-sectional area subject to shear, would undoubtedly not have as much strength as desired for preventing the inner race from rotating relative to the axle under the wheel failure conditions described above.
U.S. Pat. Nos. 4,367,905; 4,502,738; and 5,178,472 disclose a multi-sided (non-circular) shaft upon which an inner race of a bearing or bearing wheel is mounted to prevent relative rotation therebetween. U.S. Pat. No. 4,798,149 may also be of interest.
U.S. Pat. No. 3,951,076 discloses a trolley comprising a trolley body, a shaft, and a wheel on each end of the shaft. The wheel comprises an inner race having an opening through which the shaft extends, an outer race, and rollers between the inner and outer races. A cap screw is threadedly engaged in an axially extending opening in an end of the shaft, and its cap bears against a conical washer which in turn bears against a frusto conical surface of the inner race to retain the inner race on the shaft. The screw has threads which are shaped to lock against the threads in the shaft opening in order to lock the screw against rotation thereof.
In the trolley construction of this U.S. Pat. 3,951,076, no means are disclosed for preventing rotation of the inner race relative to the shaft.
It is accordingly an object of the present invention to reliably provide an early warning (before the wheel falls off) that a bearing wheel has failed.
It is another object of the present invention to provide such a bearing wheel which may be disassembled (without destroying the wheel and/or axle) and repaired.
It is a further object of the present invention to provide such a bearing wheel which is reliable, i.e., it reliably prevents rotation of the inner race relative to the shaft on which it is mounted even under conditions of bearing failure as described above, and it reliably prevents axial movement of the inner race relative to the shaft.
It is yet another object of the present invention to provide such a bearing wheel which is rugged and inexpensive.
In order to provide such a bearing wheel, in accordance with the present invention, the inner race is held on the axle by a key or other suitable means for preventing rotation of the inner race on the axle and by a screw or other suitable means for preventing axial movement of the inner race relative to the axle. The screw is prevented from rotation by a key or other suitable means.
The above and other objects, features, and advantages of the present invention will be apparent in the following detailed description of the preferred embodiment of the invention when read in conjunction with the accompanying drawings wherein the same reference numerals denote the same or similar parts throughout the several views.